casework summary or notes on your application file, as made by VO/CIC. it can be used to determine progress, status, decision rationale and to other purposes, as they relate to your application. more detailes on other systems (related to GCMS) below...
CAIPS is short for 'Computer Assisted Immigration Processing System'. It is the computer system historically used by Citizenship & Immigration Canada to process visa applications, and holds all the information on the current status of every immigration application being processed by overseas offices (i.e. those outside of Canada), other than new applications at offices which have switched to using the 'GCMS' system.
FOSS is the computer system historically used by CIC offices in Canada to track all immigration-related information, but like the CAIPS system, it is being superceded by GCMS.
GCMS is short for 'Global Case Management System', and is a newer computer system that CIC are rolling out across their offices.